Telephone-exchange system



C. B. FOWLTER TELEPHONE EXCHANGE SYSTEM Filed Sept. 25 1919 /n Vemar.' C/are/vce 5. Fow/er.

by Affy.

Patented dan. 20, i925,

CLARENCE Bi. FOXVLER, OF NEW YORK,

COMPANY, ENCORPOBATED, DE NEE*- YORK, N. A CGEFORATION OF NEW' YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed September To ZZ ui/mm t may concern:

Be it known that l, CLARENCE E. Fownnu. a citizen of the United States, residing at New York. in the county ot New York, State of 'New York. have invented certain new and useful Improvements in Telephone Exchange Systems, ot which the following is a itull, clear, concise7 andeXact description.

This invention relates to telephone change systems and more particularly to such systems in which connections between telephone lines terminating at manual and automatic exchanges are established by way of trunk circuits, over which automatic switches are controlled from the manual ei:- change for effecting connections between the trunk circuits and telephone lines at the automatic exchange.

The obj ect of this invention is the production of an improved system ot this character by which the operators at the manual exchange may control automatic switches provided at the automatic exchange and in which complete supervision over the connection is given tothe operators at the manual exchange.

In accordance with the various features ot this invention which is in the nature of an improvement ot that of an application ot' H. L. Holman. Serial No. 322,092. tiled September C. 1919, an operators impulse sending device provided at the manual eX- change and common to the link circuits thercat. is rendered individual to a link cir cuit when connected with a trunk circuit eX- tending to the automatic exchange by means responsive to the initial actuation or the irnpulse sendingl device. Means provided at the manual ottico and controlled over the trunk circuit in turn controls the disconnection of the impulse sending device from the particular engaged link circuit. and t'urther means under the control ot the operator is provided whereby. it the sending device has not been disconnected by the means controlled over the trunk circuit prior to the time that the operator desires to connect the sending device with another link circuit. the operator may disconnect the sending device from the engaged link circuit. Condensers are provided in the talking conductors ot the trunk circuit which normally prevent the flow ot direct current from the manual to the automatic exchange7 and when transmitting 232 1919. Serial No. 325,610. selecting impulses the trunk circuit beyond the condensers is intermittently opened and closed under control ot a relay controlled over one of the talking conductors ot the engaged link and trunk circuits by an impulse sending device.

For a .more complete understanding of this invention reference should be had to the tollowing description and to the accompanying drawing which illustrates one embodiment of the invention.

There is shown in the drawing a telephone line A which terminates at a manual exchange, where it may be connected with a link circuit B in any suitable and well known manner. The calling end ot the link circuit B may be connected with a trunk circuit C extending from the manual to an automatic exchange, at which are provided the usual selector and connector switches for effecting connection between the trunk circuit and telephone lines, such as l). terminating at the automatic exchange. The apparatus shown to the lett ot the vertical dotted line is located at the manual exchange. and that to the right ot this line at the automatic exchange. The nature ot this invention is such that it is believed that a clear understanding thereot will be obtained from a description ot the operation ot the system shown in the drawing. and it will he so de scribed.

The subscriber at the station on telephone line A having initiated a call and the answering end ot' the link circuit B having been associated therewith in any well known 1nanner, the operator actuates listening key 5, connecting the operatoi"s telephone set in circuit so that they operator may converse with the calling subscriber to ascertain the number of the line with which connection is desired. Assuming that connection is desired with telephone line D. which terminates at the automatic exchange, the operator inserts calling plug (ict the link circuit B into jack 7 of the trunk circuit C. Calling supervisory lamp 8 lights and sleeve relay 9 operates over a circuit from battery through the lamp 8, resistance l0, sleeve contacts ot the plug 6 and the liack 7 and winding ot relay 9 to ground. The operation ot relay 9 causes the operation ot slow release relay l2 over a circuit from battery through the right-hand contact or relay 9. winding of relay l2 and normal contact of relay 13 to ground. The operation of relay 12 establishes a short circuit for the windings of the polarized relay 13.

The operator may now actuate impulseI sending device 15, which is common to the link circuits at the operators position, preparatory to sending out the impulses necessary for selecting telephone line D and for effecting connection of the trunk circuit C therewith. Upon ,the initial actuation of the impulse sending device 15, olf-normal contact 16 closes and remains closed during the entire movement of the sending device or until it returns to normal position, causing the energization of sending device connecting relay 17' over a circuit from battery through the normal Contact of the polarized signal-control relay 13, ring talking conductor of the trunk circuit C, ring contacts ot the jack 7 and the plug 6, ring talking conductor of link circuit B, winding of relay 17, middle-normal contact thereof, lower Contact of listening key 5, oit-normal contact 16 and normal contact of pilot relay 2O to ground. Relay 17 in operating opens the talking conductors of the link circuit B and establishes a locking circuit for the relay which may be traced from battery through the normal contact of polarized relay 18, ring contacts of the jack 7 and the plug 6, winding of relay 17 contact 21 there of, contact of key 22 and the winding of pilot relay 20 to ground. Pilot relay 2O energizes over the circuit opening a Contact in the original energizing circuit of relay 17 and causing the lighting of impulse sending device pilot lamp 23.

The closure of contact 24; of relay 17 connects the impulse contact of sending device 15 with the tip t-alking conductor of the engaged link and trunk circuits, thereby causing the operation of relay 13 over a circuit from battery through the winding of relay 13, normal contact of relay 25, tip talking conductor of the trunk circuit C, tip contacts of the jack 7 and the plug (3, tip talk ing conductor of the link circuit B, contact 24 of relay 17, and the impulse contact 32, of sending device 15 to ground.

Relay 13 in operating opens the circuit `of slow release relay 12 which, in releasing i opens its contact, removing the short circuit The direction of flow of current through the reversing relay 31.

the winding of polarizedrelay 18, however, is not such as to permit the operation of this relay. The impulse response relay 30 is responsive to the impulses transmitted through the opening and closing of the impulse contact 32 of the impulse sending cle-- vice 15 and controls the usual motor magnets for the selector and connector switches provided at the automatic exchange for se lecting the desired telephone line thereat r and effecting connection of the trunk circuit with the selected line.

During the return movenient of the sending ydevice 15 to its normalpositioin the impulse Contact 32 thereof Yis intermittentlyr opened and closed to transmit the proper Y number of impulses. Upo-n'the first openmg of this impulse contact 32, relay 13 rc- ].eases causing the dcenergization of impulse` responsive relay 30. Relay 13 in closing its left-hand contact causes., the energization ot .slow release relay 12 which reestablishes the short circuit about the windings of the polarized relay 18. The purpose of this short to elnnmate the` resistance of the if of this relay 13 from the circuri y `tus associated witlrthe selector' and connecV tor switches.

After the sending of all of the impulses, telephone line D is selected and trunk circuit C is connected therewith by means of the switches 33 and 34. In the final return of the .impulse sending device 15 from its normal position, impulse contact 32 remains closed. Consequently, relay -173 remains en-A ergized to maintain the continuity of the ring talking conductor of the trunk circuit C. The continued energization of relay 13 causes relay 12 to open its contact removing the short circuit from about the windings of the polarized signal-control relay 13. After the selecting' impulses have been transmitted 'the operator mayl restore listening key 5 to normal position provided this has not already been done. the station of telephone line D may beoperated in the usual'manner. in responding to the operation of this call bell removes the receiver from the Vswitchhook, thereby causing the energization of This relay reverses the connection of the battery over the talk;

The subscriber v- It will'be seen therefore that lim; i

The call bell Vat Y Yrelease their armatures.

extinguished.

ing conductors of the trunk circuit, whereupon the direct-ion oi the iiow ot current through the windings of polarized relay 18 is such as to cause the operation thereot.

The opening' o't the normal contact of polarized relay 1S opens the locking circuit including` the sending device connecting relay 17 and pilot relay 20, whereupon both The release of pilot relay 2O extinguishes pilot lamp 23, while the release of relay 17 disconnects the sendingdevice 15 from the link circuit B and reestablishes the'continuity of the talking` conductors of the link circuit B. The closure ot the alternate contactot polarized relay 18 connects relay 25, which is ot high impedance to talking currents, in bridge of the talking conductors of the trunk circuit C on the manual side ot condensers 34 and 35. Supervisory relay 36 and bridge relay 25 thereupon operate over a circuit from battery through the winding of supervisory relay 36, lower normal contact of ringing key 37, lower normal contact of relay 17, ring contacts of the plug 6 and the jack 7, alternate contact of polarized relay 18. winding of relay 25, tip contacts ot the jack 7 and the plug 6, upper normal contact of relay 17 and upper normalccntact of ringing key 37 to ground. The energization. of supervisory relay 36 connects resistance 3S .in parallel with the lamp 8, Vwhich is thereby The extinguishment of this lamp is a "signal to the operator that the called subscriber has answered. The relay 25 in closing its alternate con-- tact, establishes a holding circuit for relay 13 before this latter relay Vis disconnected from the tip talking conductor ot the trunk circuit. The relays 17 and 13, which control the sending of the impulses from the manual exchange over thc trunk circuit to the automatic exchange, are now disconnected from the talking circuit.

At the conclusion of the conversation the subscribers restore the receivers to the switchhooks. rIhe restoration of the receiver to the switchhook at the sta-tion oi telephone line D causes the deenergization ot reversing relay 31, which thereupon reverses the connection of battery with the talking conductors of the trunk circuit. Polarized relay 18 thereupon releases its armature causing the deenergization of supervisory relay 86 and relay 25. The deenergization ot supervisory relay 3G causes the supervisory lamp 8 to light to furnish a disconnect signal. The deenergization ot relay 25 opens the circuit ot and releases relay 13. Relay 12thereupon operates to establish a short circuit for the windings or, polarized relay 18. Impulse responsive rel ay 30 at the automatic exchange remains energized. The operator upon observing the lighted condition of the supervisory lamp withdraws the plug (15 from the jack 7 whereupon the ap'- paratus associated with the calling end ot the link circuit B and that associated with the trunk circuit C restores to normal position.

Should the operator, prior to the response ot the called party, have desired to employ the sending device 15 in connection with ai; other link circuit at that position, the aetuation of key 22 causes the impulse seuding device 15 to be disconnected from the link circuit B. This is brought about by the tact that the contact of key 22 is in the locking circuit including the win dings of relays Q0 and 17 which, upon being opened, causes the release of both relays in the manner before described.

That is claimed is:

1. In a telephone exchange system, in combination, a trunk circuit, a link circuit connected therewith, an impulse sending device, a relay for connecting the device with the link circuit. and a locking circuit tor the relay including a portion ot a talking conductor ot the link circuit.

2. In a telephone exchange system, in combination, a trunk circuit, a link circuit connected therewith, an impulse sending device, and arelay energized over a portion of a talking conductor at the engaged link and trunk circuits tor connecting the device with the link circuit.

3. In a telephone exchange system, in combination, a trunk circuit, a link circuit connected therewith, an impulse sending device, a relay energized in response to the actuation of the sending device for connecting` it with the link circuit, and a locking circuit for the relay including a portion ot a talking conductor of the engaged link and trunk circuits.

4. In a telephone exchange system. in combination, a trunk circuit. a link circuit connected therewith. an impulse sending device, a relay energized in response to the actuation ot the sending device .tor connecting it with the link circuit and a polarized signalcontrol relay bridged across the trunk circuit and controlled thereover `for disconnecting the sending device from the link circuit.

5. In a telephone exchange system, in combination, atrunk circuit, a link circuit connected therewith, an impulse sending de vice, a relay energized in response to the actuation of the sending device for connecting` it with the link circuit, a telephone line connected with the trunk circuit. and a polarized signal-control relay in the trunkcircuit and controlled thereover. by the telephone line for disconnecting the sending device from the link circuit.

`6. In a telephone exchange system. in combination, a called line. a trunk circuit.l a link circuit connected therewith, an im lil() lill) pulse sending device, means for connecting theV sending device withy the link circuit, and means in Jthe trunk circuit and controlled by the 'called line tor disconnecting the sending device from the link circuit.

7. In a telephone exchange system, in combination., a trunk circuit, a link circuit connected thereivitlnan impulse sending device, means for connecting the sendingdevice Vwith the link circuit, a called telephone line connected With, the trunk circuit and a signal-control relayv in the trunk circuit controlled thereover by the closure of the telephone line for disconnecting the sending device from the link circuit.

8. In a telephone exchange system, in combination` a trunk ,circuit comprising talking conductors, an operators'link cir` cuit connected with .the trunk circuit,'an impulse sendingdevice, an impulse responsive relay, an ,impedance device, permanently bridged acrossthe talking conductors ot the i trunk, circuit, means operated in response' to the actuation ofthe impulse sending device for connecting it with the link circuit, `means controlled by and effective during the operation ot the sending device tor establishing a non-inductive path aroundthe impedance device, and means controlled by the sending device 'or openingy and closing the circuit .including the talking conductors and vthe noninductive path for controlling. the. impulse responsive relay. Y Y Y 9. In a .telephone exchange system, in combination` a trunk circuit .comprising talking conductors, an .operators link circuit connectedy with the trunk circuit, an impulse responsive relay, a normally closed bridge of the talking conductors, an 'limpulse sending device, means operated intresponse to the actuation of the impulsel sending device for connecting it with 'the link circuit, and means controlled by the sending` device for short-circuiting said bridge and Ytorinterrupting the lcontinuity ot one of the talking conductors during, the operation of the sending. device for controlling the` impulse responsive relay.

l0. In a telephone exchange system, in combination, a trunk circuit comprising a ,pairv of talkingconductors, a link circuit connected with the trunk circuit, a super visory signal therein, an impulse responsive relay, a signal-control relay bridgedv across the talking conductors responsive to a reversal of current over said trunk circuit for controlling said signal, an impulse sending device, means operated in response to the actuation oi the impulse sending device for connecting it With the link circuit, means f responsive to the operation of the sending device for transmitting ,impulsesI over the trunk circuit for controlling the lmpulse responsive relay, and means controlled by and rendered effective during the operation of the sendlng device for short-cireuitmg the signal-control relay.

ll. In a telephone exchange system, in

combination, a trunk circuit comprising a talking conductor including a. ,normally open contact, a link circuit connected With the trunk circuit, av relay in the. trunk circuit initially energized over Va circuit including a portion ef the link circuit for closing the normally open talking conductor, and means controlledl over the trunk circuit for maintaining the relay in energized condition independent of its original ener gizing circuit. Y

l2. In a'telephone exchange system, in combination, a trunk circuit comprising a pair of talking conductors, a normally open contact in one of the talking conductors, a link circuit connected With the trunkV circuit, an impulse sending` device, an impulse responsive relay, a. control relay controlled by the impulse sending device for intermittently closing the contact to control the impulse responsive relay," and means con-- trolled over the trunk circuit for removing Y the control relay fromthe control of the sending device and for maintaining it in energized condition to close the Contact.

13. In a telephone exchange system, a calling line. a called line, means including an operators Vlink circuit and atrunk circuit for establishing connection between said lines, a supervisory signal in said'link circuit, a repeating relay in said trunk crcuit, a bridge in said trunk circuit forcentrolling said signal, an impulse sender, a circuit therefor extendingover one Atalking conductor of said link circuit and said trunk circuit for controlling said repeating relay, means operated in response to the actuationotthe impulse sender for connecting the impulse sender and the control circuit, and means controlled by 'said repeating relay 'for repeating saidimpulses over the tivo sides of said trunk circuit in series and for short-eircuiting said bridge 'during the sending of impulses.

14. In al telephone exchange system, a calling and a called subscribers line, means including an operators link circuit and a trunk circuit for interconnecting said lines, a supervisorv signal in said link circuit, an impulse responsive relay, a relay bridged across the trunk circuit responsive to a reversa-l ot current for actuating said signal, an impulse sender, means operated inresponse to the actuation of said impulse sender for connecting it with said link cir- Y cuit, means responsive to the operation of the sending device forcontrolling said impulse responsive relay, and means c ontrolled by and rendered eifective during the operation of said sending device'r'or shortcircuiting` said bridged relay.

15. VIn a telephone exchange system, aof the talking Conductors of the link cirplurality of subscribers lines, means ineluding an operators link circuit and a trunk circuit for establishing a connection between the calling and a called line, a repeating relay in said trunk circuit, an impulse sender, a circuit therefor extending over one talking conductor of said link circuit and said trunk Circuit for controlling said repeating relay, means operated in response to the actuation of the impulse sender for connecting the impulse sender and the control circuit, condensers in the talking conductors of the trunk circuit, a supervisoryT signal in the 'link circuit, a bridge between the talking conductors of the trunk circuit and intermediate the calling line and said condensers7 a relay in one cuit for controlling said signal, a normally open bridge between the talking conductors of the trunk circuit intermediate said condensers and the called line, a relay in said second bridge responsive to a reversal of current over said Called line for Closing said firstmentioned bridge to operate the relay in the link circuitover the two talking conductors of the link Circuit in series, and means controlled by said repeating relay for short-circuiting said second mentioned bridge during the operation of said repeating relay.

In Witness whereof` I hereunto subscribe my name this 19th day of September A. D.,

CLARENCE B. FOWLER. 

